OFFSET
1,1
COMMENTS
In such cases it seems that initial value equals peak value. Proof needed!
EXAMPLE
n=72: list={72,36,18,9,28,14,7,22,11,34,17,52,26,13,40,20,10,5,16,8,4,2,1}
MATHEMATICA
c[x_]:=c[x]=(1-Mod[x, 2])*(x/2)+Mod[x, 2]*(3*x+1); c[1]=1; fpl[x_]:=FixedPointList[c, x]; {$RecursionLimit=1000; m=0}; Do[If[PrimeQ[1+Max[fpl[n]]&&PrimeQ[ -1+Max[fpl[n]]], Print[n]], {n, 1, 10000}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jun 14 2004
STATUS
approved